Robert Gunsalus Phd

Research Interests

Research interests of the Gunsalus laboratory address the
physiology and molecular biology of gene expression in the Bacteria and
Archaea. We are studying how cells sense changing environmental conditions, and
adapt their metabolism accordingly. Experimental approaches being used include
whole genome DNA microarrays, classical microbial genetics, biochemistry, and
molecular/structural biology. Model organisms include the methanogenic Archaea
(Methanosarcina acetivorans and Methanosarcina mazei) and enteric bacterial
species including Escherichia coli K-12. The former two microbes produce
methane from the biological precursors, acetate, methanol, methyl-amines, and
in most instances, H2/CO2. We are identifying the gene families involved in use
of the alternative carbon substrates leading to methane formation with the goal
of understanding the regulatory networks and the key regulatory factors. The
Methanosarcina are also versatile in their ability to withstand stress; for
example, they can grow fresh water environments, marine environments, and to
hyper saline environments (ca to 1.2 M NaCl). They do so by synthesis and/or
transport of osmolytes (i.e., N-acetyl-beta-lysine, alpha-glutamate, betaine,
and potassium) whereby the levels of these osmolytes are modulated over a wide
range to adjust osmotic balance. Finally, we are examining the regulatory
mechanisms that allow the common enteric bacterium, E. coli to switch from
aerobic to anaerobic growth. This ability allows comensual as well as
pathogenic strains to adapt and grow successfully inside and outside the human
body by using a variety of genetically programmed strategies.